1. Field of the Invention
The present invention relates to a photosensitive insulating resin composition, a cured product obtained by curing the photosensitive insulating resin composition, and a method of producing an insulating film.
2. Discussion of the Background
A polyimide resin that exhibits excellent heat resistance, mechanical properties, and the like has been widely used as an interlayer dielectric, a surface protective film, or the like that is used for semiconductor devices provided in electronic instruments. Various photosensitive polyimide resins provided with photosensitivity have been proposed in order to improve productivity, film formation accuracy, and the like. For example, Japanese Patent Application Publication (KOKAI) No. 5-5996 discloses a negative-tone resin in which a photo-crosslinkable group is introduced into a polyimide precursor via an ester bond or an ionic bond, and Japanese Patent Application Publication (KOKAI) No. 2000-98601 discloses a positive-tone resin that contains a polyimide precursor and an o-quinonediazide compound.
Along with an increase in the degree of integration of semiconductor devices, various photosensitive polyimide resins have been proposed in order to further improve the film formation accuracy. For example, Japanese Patent Application Publication (KOKAI) No. 54-145794 discloses a composition that contains a photosensitive polyimide resin in which a photo-crosslinkable group is introduced into a polyimide precursor via an ionic bond, and Japanese Patent Application Publication (KOKAI) No. 3-186847 discloses a composition that contains a photosensitive polyimide resin in which a photo-crosslinkable group is introduced into a polyimide precursor via an ester bond. Japanese Patent Application Publication (KOKAI) No. 8-50354 discloses a negative-tone photosensitive composition that contains an aromatic polyimide precursor and a polyfunctional acrylic compound. As a composition that does not contain a polyimide, Japanese Patent Application Publication (KOKAI) No. 2003-215802 discloses a photosensitive insulating resin composition that contains a phenolic hydroxyl group-containing alkali-soluble resin, a crosslinking agent, and a photoacid generator.
In the semiconductor field, the wafer size has been increased in order to improve yield. Therefore, the difference in coefficient of linear expansion between the wafer and an insulating film formed on the wafer has posed a problem. Specifically, when forming an insulating film on a wafer, the wafer is tensed by the insulating film that has a coefficient of linear expansion larger than that of the wafer. Since the wafer is tensed to a larger extent as the wafer size increases, the wafer is warped as a result of forming the insulating film on the wafer.